Flexible sheet securing means



June 13, .1933. I A. G. JACOBSON FLEXIBLE SHEET SECURING MEANS i'iid Nov. 8, 1950 fizz/67.275: drihzr 6 1260295022,

ing

Patented June 13, 1933 UNITED STATES PATENT OFFICE ARTHUR G. JACOBS'ON, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE MIEHLE PRINTING PRESS & MFG. COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS FLEXIBLE SKEQJT SECURING MEANS Application filed November 8, 1930. Serial No. 494,241.

This invention relates to means for securand positioning a flexible sheet on a printing member or the like. The invention more specifically concerns that type of mechanism commonly used in connection with rotary rinting presses for securing a flexible printing plate to a cylinder.

In connection with such presses, the printing plate has to be frequently removed and replaced by another plate for a different job, and in order to eliminate any unnecessary waste of time, it is desirable that such plates can be very readily and expediently removed and replaced.

In constructions known and used heretofore, the removal and replacing of a printing plate demanded considerable time because a large number of clamping bolts, etc. have to be loosened in order to release the Iejdges of the sheet applied to a printing mem- It is therefore the primary object of my invention to provide securing means for a flexible printing plate or the like which can be very quickly released as well as expediently applied to such plate.

A further object of the invention resides in the provision of a quick release plate clamp whereby the necessity of a large number of clamping bolts, etc. shall be eliminated.

Another object of my invention is to provide in combination with the quick release features of my improved plate securing mechanism means whereby each individual clamp applied to the edge of a flexible sheet can be individually adjusted longitudinally of such edge for the purpose of straightening the edge i. e. eliminating buckles in the sheet.

Other objects of my invention will become apparent from the following description and appended claims.

For the purpose of exemplying the principle 'of my invention, I have shown it as ap plied in connection with a printing cylinder of a rotary press, and I have illustrated two forms of constructions in the accompanying drawing, of which:

Figure 1 is a cross sectional view taken through the cylinder and showing the manner of arranging the sheet securing means within the gap of such cylinder;

Figure 2 illustrates a modified form of construction embodying my invention and including certain adjusting means not applied in connection with the design shown in Figure 1; and

Figure 3 is a partial cross sectional view taken along line 3--3 of Figure 2 and showmg the means whereby individual transverse adjustment of the sheet securing elements can be accomplished.

Referring now to Figure 1 of the drawing, the cylinder 10 in connection with which I have illustrated my invention by Way of example, is formed with a recess or ap 11 provided with a machined base sur ace 12, on which I preferably mount the sheet securing means.

The clamping and adjusting means are mounted on a block 13 which in this particular form of construction is secured to the base 12 by means of bolts 14,. or the like. Said block in turn carries a bracket 15 which is preferably bolted to the block 13, and on which I provide a stud 16, whereon the lower clamping member 17 is pivoted. An upper clamping member 18, which cooperates with the member 17, is pivotally mounted on the latter at 19, the member 18 having a downwardly projecting extension 20 into which is threaded a clamping i. e. adjusting spindle 21.. The spindle 21 is operated by means of a hand wheel 22 preferably provided with pin wrench holes as indicated, and the free end 23 of said spindle abuts against a machined face 24 provided in the Wall of the cylinder for the purpose as hereinafter described. By means of a coil spring 25, fitted within recesses formed in the lower clamping member 17 and in the member 18, the latter is held under tension so that the jaws 26 and 27 of said clamping members will cooperate to engage and firmly hold the edge of the flexible sheet 28, irrespective of whether or not pressure is applied by means of the spindle 21.

Preferably I provide in the block 13 an elongated slot 29 so that a limited adjustment of said block relatively to the face 24 can be obtained.

In plate securing means heretofore known and used in practice, the angle formed between the axis of the clamp tightening i. e. adjusting spindle or screw and the abutting surface with which such spindle cooperates, is usually 90 or more. In such constructions, however, as indicated above, it is necessary to fully loosen the clamping i. e. adjusting screws or bolts before the plate can be removed from the securing means and therefore considerable time is wasted in the removal'and replacing of a plate. I have found that by arrangin the cooperating parts so that the angle formed between the axis BB of the clamp tightening or adjusting spindle 21 and the plane AA of the bearing face 24 is always less than 90 when said spindle is in its operative position, the clamping effect between the members 17 i. e. jaws 26 and 27 will be released by giving the hand Wheel 22 only a partial turn,that is to say less than one-fourth of a revolution, just sufficient to release the pressure exerted by the spindle 21 against the bearing face 24, and by then slightly tapping the wheel 22 with the hand, whereupon the aws 26 and 27 will fully open and the sheet 28 will be entirely freed for removal.

On the othenhand, it will be readily seen that by this arrangement the outer end 23 of the spindle 21 will firmly wedge itself in an upward direction against the inclined face 24 when tension is applied to the spindle in order to stretch i. e. tighten the flexible sheet 28. It will also be understood that simultaneously with the tightening of the sheet 28 by means of the spindle 21 the clamping pressure between the jaws 26 and 27 will be increased and vice versa.

I therefore accomplish a multiple purpose, namely, by tightening the clamping members onto the sheet, the sheet will simultaneously be stretched or vice versa, and by increasing the tension on the spindle 21, the outer end of the spindle will wedge itself against the face 24 as explained above, thereby automatically locking the spindle 21 against inadvertent loosening.

According to the modified form of construction illustrated in Figure 2 of the drawing, I also provide means whereby the block 13 can be conveniently positioned over the base 12 in order to adjust the clamping means with relation to the circumference of the cylinder. Such positioning of the block 13 and therewith of the clamping means as a whole is very desirable inasmuch as usually the length of printing members such as plates variesand consequently without such adjustment of the clamping means, trimming of the plate edges would be necessary, this I eliminate with the construction shown in Figure 2.

The adjustable block 13 in this case is formed with an upwardly extending arm or bracket 30, the inner face 31 of which is machined in order to provide a bearing face for the clamping spindle 21. It will be readily understood that due to the considerable pressure exerted by the spindle 21 against its bearing face, indentations will eventually be formed in said face, thereby affecting the proper operation of the plate securing means. In order to eliminate this defect, I provide a ball end 32 on the spindle 21 which engages within a socket formed in the block 33, which latter can readily slide over the face 31, thereby following the movement of the spindle 21 when the latter is operated to tighten the jaws 26 and 27 onto the sheet 28.

In addition to the spring 25 as shown in Figure 1, I provide in the modified form ust described a coil spring 34, one end of which is preferably housed within a recess formed in the lower clamping member 26, while the outer end of said spring bears against an upwardly extending abutment 35 so that in this form of construction, when the spindle 21 is loosened and after the sheet 28 has been freed, the lower clamping member 26 will be moved about its pivot 16 towards the cylinder wall in the gap.

The positioning of the block 13 over the base 12, and therewith the adjustment of the clamping members circumferentially of the cylinder 10, is accomplished by an adjusting spindle 36, the outer end of which is supported in a bracket 37 preferably bolted to the base 12, while its inner end may i be carried by a bar 38 adjustably mounted on the face 39 of the cylinder wall for the purpose which will be hereinafter explained. The spindle 36 is operated by means of a hand wheel 40 which is preferably provided with pin wrench holes similar to the hand wheel 22 whereby the clamping members are operated.

\Vith this modified form of construction, I also accomplish the same purpose as with the arrangement shown in Figure 1, namely by tightening the clamping members 17 and 18 by means of the spindle 21, tension is also simultaneously applied to the sheet 28.

Furthermore, it will be seen that by ten-' sioning the spindle 21 the adjusting spindle 36 will also become locked automatically against inadvertent loosening because by the forces transmitted to the block 13, due to the tension applied by the spindle 21 to the arm 30 of said block, considerable friction i. e. wedging action will be set up between the thread in the block 13 and the thread on the spindle 36. As a matter of fact, due to these forces there will be a tendency to tilt the block 13 about its edge adjacent the face 39 and to thereby bend the spindle 36, which will add additional friction between the threads in the block 13 and on the spindle 36, and thereby will render the locking action more effective. When the spindle 21 is released, however, these forces will again be eliminated and the spindle 36 will be free to rotate.

With the arrangements described above, I therefore provide a quick release clamp which will operate to also automatically lock the tightening i. e. adjusting spindles against any inadvertent loosening during the operation of the press.

According to Figure 3, the individual adjustment of the clamping members 17 and 18 is accomplished by mounting one end of the lower clamping member 17 on the stud 16 in a manner that the latter can be adjusted relatively to the block 13. In order to accomplish this, I provide a threaded inner portion on said stud which screws into a threaded recess 42 formed in the block 13, while the other end of the member 17 is slidably mounted on a stud 43 which is preferably keyed within a bore 44 formed in the block 13. The threaded stud 16 carries at its outer end an adjusting wall 45 which is preferably provided with pin wrench holes 46 whereby the required adjustment of the clamping member 17 can be accomplished.

In practice I also preferably provide means whereby all of the clamping members arranged along one edge of the plate 28 may be adjusted as a unit transversely of the base 12 i. e. cylinder 10. The means for accomplishing this, however, is described and covered in a prior patent, namely Letters Patent 1,7 25,7 79 issued to J. R. Blaine, which explains the purpose of adjust-ably mounting the bar 38 as indicated above.

It will be readily understood that while I have shown two different forms of construction embodying my invention, other modifications may be resorted to without, however, departing from the principle of my invention, and scope of the appended claims.

I claim:

1. In combination with a support, means for securing a flexible sheet thereto, including a clamp mounted on a movable block, a tensioning member associated therewith for positioning a sheet on said support, and a bearing face for said tensioning member, the angle formed between the axis of said tensioning member and said bearing face being always less than when said member is in its operative position.

2. In combination with a support, means for securing a flexible sheet thereto, including a plurality of associated clamping members mounted on an adjustable base, a tensioning screw associated with one of said members, and a bearing face for said tensioning screw, the angle formed between the axis of said screw and said bearing face being always less than 90 when said screw is in its operative position.

In combination with a support, means for securing a flexible sheet thereto, including a plurality of associated clamping members mounted on an adjustable base, a tensioning screw carried by one of said members, and a bearing face for said tensioning screw, the angle formed between the axis of said screw and said bearing face being always less than 90 when said screw is in its operative position.

4. In combination with a support, means for securing a flexible. sheet thereto, including a lower clamping member mounted on an adjustable block and an upper clamping member pivotally associated therewith, a tensioning screw carried by one of said members, a bearing face on said support for said tensioning screw, the angle formed between the axis of said screw and said bearing face being always less than 90 when said screw is in its operative position.

5. In combination with a support, means for securing a flexible sheet thereto, including a plurality of clamping members, an adjusta ble block supporting said members, a tensioning element associated with said clamping members for positioning a sheet on said support, and a bearing face on said block for said tcnsioning element, the angle formed between the axis of said element and said face being less than 90 for the purpose set forth.

(5. In combination with a support, means for securing a flexible sheet thereto, including a plurality of clamping members, a movable block supporting said members, a tensioning clement associated with said clamping members for positioning a sheet on said support, means for adjusting the position of said block, and a bearing face on said block for said tensioning element, the angle formed between the axis of said element and said face being less than 00 for the purpose set forth.

7. In combination with a support, means for securing a flexible sheet thereto, including an adjustable block arranged to move relatively to said support, a clamping member pivotally associated with said block, a sec ond clamping member associated with said first mentioned clamping member, a tensioning element associated with said members for positioning a sheet on said support, a bearing face on said block for said tensioning element, the angle formed between the axis of said tensioning element and said bearing face being less than 90 for the purpose set forth.

8. In combination with the support for a flexible printing member or the like, a plurality of securing elements to hold a flexible member on said support and comprising clamping members, a block on which said clamping members are mounted, a tensioning element, operatively associated with said clamping members and block to position a printing member on said support, a bearing face on said block for said tensioning element, and means foradjusting said securing elements transversely of said support.

9. In combination with the support for a flexible printing member or the like, a plurality of securing elements to hold a; flexible member on said support and comprising clamping members, a block on which said clamping members are mounted, a tensioning element, operatively associated w1 tl1 said clamping members and block to position a printing member on said support, a bearmg face on said block for said tensioning element, and means carried by said block for adjusting said securing elements transversely of said support.

10. In combination with the support for a flexible printing member or the like, a pinrality of securing elements to hold a flexible member on said support and including a plurality of clamping members, a movable block supporting said clamping members, a tensioning element associated with said members for positioning a printing member on said support, means for adjusting the position of said block, a bearing face on said block for said tensioning element, and means for adj usting said securing elements transversely of said support.

11. In combination with the support for a flexible rinting member or the like, a plurality of securing elements to hold a flexible sheet on said support and including a plurality of clamping members, a movable block supporting said members, a tensioning element associated with said members for positioning a sheet on said support, means for ad j usting the position of said block, a bearing face on said block for said tensioning element, and means carried by said block for adjusting said securing elements transversely of said support.

12. In combination with the support for a flexible printing member or the like, a plurality of securing elements to hold a flexible sheet on said support and including an adjustable block, a lower clamping member pivotally associated therewith, an upper clamping member, a tensioning element operatively associated with said clamping members for positioning a flexible sheet on said support, a bearing face on said block for said tensioning element, means for adjusting the position of said block, and means for relatively adjusting said securing elements transversely of said support.

13. In combination with the plate supportin g member of a printing press or the like, a plurality of plate securing elements to hold a plate on said supporting member and including clamping members, a block on which said clamping members are mounted, a tensioning element, operatively associated with said clamping members and block to position a plate on said supporting member, a bearing face on said block for said tensioning element, and means for adjusting said plate securing elements transversely of said supporting member, the angle formed between the axis of said tensioning element and said bearing face being less than 90.

14. In combination with the plate sup orting member of a printing press or the li e, a plurality of plate securing elements to hold a plate on said supporting member and including clamping members, a block on which said clamping members are mounted, a tensioning element, operatively associated with said clamping members and block to position a plate on said supporting member, a bearing face on said block for said tensioning element, and means carried by said block for adjusting said plate securing elements transversely of said supporting member, the angle formed between the axis of said tensioning element and said bearing face being less than 90.

15. In combination with the plate supporting member of a printing press or the like, a plurality of plate securing elements to hold a flexible plate on said supporting member and including a plurality of clamping members, a movable block supporting said clamping members, a tensioning element associated with said members for positioning a plate on said supporting member, means for adjusting the position of said block, a bearing face on said block for said tensioning element, and means for adjusting said plate securing elements transversely of said plate supporting member, the angle formed between the axis of said tensioning element and said bearing face being less than 90.

16. In combination with the plate supporting member of a printing press or the like, a plurality of plate securing elements to hold a flexible plate on said supporting member and including a plurality of clamping members, a movable block support ng said members, a tensioning element associated with said members for positioning a plate on said supporting member, means for adjusting the position of said block, a bearing face on said block for said tensioning element, and means carried by said block for adjusting said plate securing elements transversely of said plate supporting member, the angle formed between the axis of said tensioning element and said bearing face being less than 90.

17. In combination with the plate supporting member of a printing press or the like, a plurality of plate securing elements to hold a flexible plate on said supporting member and including an adjustable block, a lower clamping member pivotally associated therewith, an upper clamping member, a tensioning element operatively associated with said clamping members for positioning a flexible plate on said supporting member, a bearing face on said block for said tensioning element, means for adjusting the position of said block, and means for relatively adjusting said plate securing elements transversely of said supporting member, the angle formed between the axis of said tensioning element and said bearing face being less than 90.

18. In combination with the support for a flexible printing member or the like, a plurality of securing elements to hold a flexible member on said support and comprising clamping members, a block on which said clamping members are mounted, a tensioning element, operatively associated with said clamping members and block to position a printing member on said support, a bearing face on said block for said tensioning element, and means for individually adjusting said securing elements transversely of said support. A

19. In combination with a support, means for securing a flexible sheet thereto, including a plurality of clamps, tensioning members associated therewith for positioning a sheet on said support, means for adjusting said clamps circumferentially of said support, means for individually adjusting each of said clamps transversely of said support, and a bearing face for said tensioning members, the angle formed between the axis of a tensioning member and said bearing face being less than 90for the purpose set forth.

20. In combination with the support for a flexible sheet, clamping members adapted to be secured to a sheet tightening means for said members, and a tensioning element associated with said members for positioning a sheet on said support, said tensioning element becoming automatically locked against movement by the actuation of a tightening means for said clamping members.

- 21. In combination with a support,'means for securing a flexible sheet thereto, including a plurality of clamping members, tightening means for said clamping members, a block supporting said members, a tensioning element associated with said clamping members for positioning a sheet on said support, and a bearing face on said block for said tensioningelement, the cooperative arrangement of said clamp tightening means and said tensioning element being such that the latter becomes automatically locked against movement by the actuation of said tightening means.

22. In combination with a support, means for securing afiexible sheet thereto, including a plurality of clamping members, tightening means for said clamping members, a block supporting said members, a tensioning element associated with said clamping members for positioning a sheet on said support, and a bearing face on said block for said tensioning element, the cooperative arrangement of said clamp ti htening means and said tensioning element eing such that the latter becomes automatically locked against movement by the actuation of said tightening means, while b releasing the tension on said clamping mem ers, the locking effect on said tensioning element will become released.

23. In combination with a support, means for securing a flexible sheet thereto, including a clamp, a tensioning member associated therewith for positioning and applying tension to a flexible sheet and for simultaneously tightening said clamp, a bearing face for said tensioning member, the angle formed between the axis of said tensioning member and said bearing face being always less than 90 when said member is in its operative position.

Signed at Chicago, Illino1s, this 4th day of November, 1930.

ARTHUR G. J ACOBSON. 

